/*
 * Copyright (c) 2010 Frederic Daoud
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */
package com.fdaoud.rayures.action;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import net.sourceforge.stripes.action.ActionBean;
import net.sourceforge.stripes.action.ForwardResolution;
import net.sourceforge.stripes.action.Resolution;
import net.sourceforge.stripes.config.Configuration;
import net.sourceforge.stripes.controller.ActionResolver;
import net.sourceforge.stripes.controller.StripesFilter;
import static com.fdaoud.rayures.extension.RayuresActionResolver.convertToLowerCaseWithUnderscores;

/**
 * Resolution that forwards to a default view. By convention, this is a combination of the action
 * bean's URL binding and the name of the event. For example, if a request is made to an action bean
 * bound to {@code /home}, and to the {@code index} event, this resolution would forward to
 * {@code /WEB-INF/jsp/home/index.jsp}. CamelCase is converted to snake_case.
 *
 * @author Frederic Daoud
 */
public class ForwardToDefaultView implements Resolution {
  private String path;
  private Resolution resolution;

  public ForwardToDefaultView(ActionBean actionBean) {
    path = getDefaultPath(actionBean);
    resolution = new ForwardResolution(path);
  }

  public void execute(HttpServletRequest req, HttpServletResponse resp) throws Exception {
    resolution.execute(req, resp);
  }

  public String getPath() {
    return path;
  }

  /**
   * Returns the combination of {@link #getBasePath(Class)},
   * {@link #getViewName(String)}, and {@link #getViewExtension()}.
   */
  public String getDefaultPath(ActionBean actionBean) {
    return getBasePath(actionBean.getClass())
      + getViewName(actionBean.getContext().getEventName())
      + getViewExtension();
  }

  /**
   * Returns "/WEB-INF/jsp".
   */
  protected String getRootPath() {
    return "/WEB-INF/jsp";
  }

  /**
   * Returns the base path from which to construct the default view path.
   */
  protected String getBasePath(Class<? extends ActionBean> actionBeanClass) {
    Configuration config = StripesFilter.getConfiguration();
    if (config == null) {
      throw new NullPointerException("Stripes Configuration is null");
    }
    ActionResolver actionResolver = config.getActionResolver();
    if (actionResolver == null) {
      throw new NullPointerException("Stripes ActionResolver is null");
    }
    return getRootPath() + actionResolver.getUrlBinding(actionBeanClass);
  }

  /**
   * Returns the view name, prepended with a slash, with CamelCase converted to snake_case.
   */
  protected String getViewName(String viewName) {
    return "/" + convertToLowerCaseWithUnderscores(viewName);
  }

  /**
   * Returns ".jsp".
   */
  protected String getViewExtension() {
    return ".jsp";
  }
}
